code: def register_preprocessor(self, inputs, outputs, preprocessor):
      raise NotImplementedError
  
file_path: autokeras/autokeras/prototype/graph_state.py
imports: import threading
  from tensorflow import keras
label_desc: Use image node_id 4 for calling the State obj's underlying member method code with example usage: obj.register_preprocessor(inputs, outputs, preprocessor) without return types